The first was the book Wordsmithy:
Since we unschool, I handed her the book and said, "If you read this, then you can give me your opinion. If you don't read it, I'll have to read it because I said I'd review it."
That was the first test of the book. Is it interesting enough for an unschooled teenager to pick up and read?
She did read through it. She was even interested enough to also look up the author and see what kind of writing he does, since he was dispensing advice. (Note: he is a devout Christian, and mentions God as part of his guidance.)
As she was going through the book, she felt that he was giving advice more about the technical aspects and less on simply writing for pure pleasure. She wondered if he writes fiction or nonfiction (which led to her googling him) and was unsurprised that he mainly writes nonfiction. She did feel that his suggestions are useful for those who want to improve in mechanics and proficiency of writing.
When she was in the middle of the book, she often commented to me about things he said that were or would be useful. She just as frequently commented that she disagreed with this or that. (When I say "commented," I mean mainly on chat, lest you think we actually speak, except for the time we went on a short walk together and she spent a good portion of it talking about the book.)
The impression that I got is that her mind was engaged in the book; she was taking him seriously and giving him the respect of looking at her own experience with writing and seeing if what he was saying fit in to that and if she thought it would be useful and true, or she didn't think a particular piece of advice would be helpful.
I have the feeling that a lot of what he said in Wordsmithy is going to be in the back of her mind as she writes, whether she agrees with him or not. His style of writing is straight, talking directly to the reader. It is compact and readable; each tip is not longer than two pages and has a takeaway point. It's the kind of information that sneaks in and settles in to your world view of how to write.
If I could sum up her opinion in one sentence (and this is an exact quote): "He has good tips."